Research On The Joint Damage Mechanism Of Equine Osteoarthritis

The equine osteoarthritis is an important disease, the disease have effect on the use of equine. The disease pathogenesis is complicated and also not easy to be found in the early of disease,therefore, the early diagnosis and treatment of disease is very important.In the process of equine osteoarthritis pathogenesis, articular cartilage lesions is the main symptom., and producing the proinflammatory factors, protein enzymes and the degradation products of the metabolism of cartilage, which will be secreted into the synovial fluid, synovial fluid is the most direct liquid to check the biomarkers,and horse have the larger joints, the volume of synovial fluid is large, so it is easy to obtain the synovial fluid.This experiment build the equine osteoarthritis model with experimentally method, to study the changes trend of biomarkers in synovial fluid in the process of equine osteoarthritis, to provide the reference for the rapid diagnosis of equine osteoarthritis.We used 13 Mongolian horses in these induction studies. Horses were randomly divided into 2 groups: The experimental group was 8 horses, the control group was 5 horses. The experimental group was to build the equine osteoarthritis model.The induction was done through intra-articular(IA) injection of 2 ml of Amphotericin-B in horses’ left carpal joints.the horse of control group was injected into 2 ml physiological saline in horses’ left carpal joints. Synovial fluid was collected every week until 9 weeks.Synovial fluid was also evaluated using ELISA kits.The biomarkers of detection include IL-1 、 PGE2 、 IL-6 、 TNF-α 、 MMP-2 、 MMP-9 、 MMP-3 、MMP-13、ADAMTS-5、CS846、CPII、C2C、HA、GAG、COMP、CTX-II、OCN.The results:(1) Upper biomarkers: Compared with the control group, in the first week after model establishment, the content of IL-1、IL-6、PGE2 increased significantly in the synovial fluid, and continued to increase after weeks. At the beginning of the first week after model establishment,increased the content of TNF-α in synovial fluid, but the increase was not obvious, from third weeks in TNF-α in synovial fluid was significantly increased, and continued to increase until ninth weeks.(2) Middle biomarkers: Compared with the control group, the content of MMP-2 and MMP-3 in synovial fluid increased from the beginning of the first week after model establishment, but the increase was not obvious, the significant increase began the third week, and kept increasing until the ninth weeks. The content of MMP-9 and ADAMTS-5in the synovial fluid increased significantly from the beginning of the first week after model establishment and kept increasing until ninth weeks. The content of MMP-13 in the synovial fluid increased from the first week, but the increase was not obvious, from the second weeks, began to increase significantly and kept increasing until the ninth weeks.(3) Downstream biomarkers: Compared with the control group, the content of CS846、HA and GAG in synovial fluid increased significantly from the beginning of the first week after model establishment, and kept increasing until the ninth weeks. The content of CPII、C2C、COMP、CTX-II and OCN in synovial fluid increased from the beginning of the first week after model establishment, but the increase was not obvious, the significant increase began the second week, and kept increasing until the ninth weeks.Conclusion:(1) In the process of osteoarthritis, the upper biomarkers in synovial fluid have the increasing trend, including IL-1、IL-6、PGE2 TNF-α. IL-1、IL-6、PGE2 increased significantly in the early stage of the disease, these proinflammatory cytokines will promote the secretion of the degradation protease.(2) In the process of osteoarthritis, the middle biomarkers in synovial fluid have the increasing trend, including MMP-2、MMP-9、MMP-3、MMP-13、ADAMTS-5. The increase of these proteases may accelerate the degradation of cartilage and subchondral bone metabolism; the increase of MMP-9 and ADAMTS-5 were significant in the early stage of the disease.(3) In the process of osteoarthritis, the downstream biomarkers in synovial fluid have the increasing trend, including CS846 、 CPII 、 C2 C 、 HA 、 GAG 、 COMP、 CTX-II, OCN. The increase of CS846、HA、GAG were significant in the early stage of the disease.